permutedims for vectors and matrices (#917)

* permutedims, easy cases

* fix

* add sizedarray methods

* tests

* bump version

Author: mcabbott

Project.toml

@@ -1,6 +1,6 @@
 name = "StaticArrays"
 uuid = "90137ffa-7385-5640-81b9-e52037218182"
-version = "1.2.8"
+version = "1.2.9"
 
 [deps]
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"

src/abstractarray.jl

@@ -224,7 +224,21 @@ for rot in [:rotl90, :rotr90]
     end
 end
 
-# TODO permutedims?
+# TODO permutedims? So far just the cases without perm:
+
+Base.permutedims(A::SVector{N}) where {N} = SMatrix{1,N}(A.data...)
+Base.permutedims(A::MVector{N}) where {N} = MMatrix{1,N}(A.data...)
+Base.permutedims(A::SizedVector{N}) where {N} = SizedMatrix{1,N}(permutedims(A.data))
+
+@generated function Base.permutedims(A::SMatrix{M,N}) where {M,N}
+    exs = permutedims([:(getindex(A,$i,$j)) for i in 1:M, j in 1:N])
+    return :(SMatrix{N,M}($(exs...)))
+end
+@generated function Base.permutedims(A::MMatrix{M,N}) where {M,N}
+    exs = permutedims([:(getindex(A,$i,$j)) for i in 1:M, j in 1:N])
+    return :(MMatrix{N,M}($(exs...)))
+end
+Base.permutedims(A::SizedMatrix{M,N}) where {M,N} = SizedMatrix{N,M}(permutedims(A.data))
 
 #--------------------------------------------------
 # Concatenation

test/abstractarray.jl

@@ -218,6 +218,24 @@ using StaticArrays, Test, LinearAlgebra
     end
 end
 
+@testset "permutedims" begin
+    # vector -> one-row matrix
+    @test @inferred(permutedims(SVector(1,2,3))) === SMatrix{1,3}(1,2,3)
+    @test @inferred(permutedims(MVector(1,2,3))) isa MMatrix{1,3}
+    @test @inferred(permutedims(MVector(1,2,3))) == [1 2 3]
+    @test @inferred(permutedims(SizedVector{3}([1,2,3]))) isa SizedMatrix{1,3}
+    @test @inferred(permutedims(SizedVector{3}([1,2,3]))) == [1 2 3]
+
+    # matrix
+    @test @inferred(permutedims(SMatrix{2,2}(1,2,3,4))) === SMatrix{2,2}(1,3,2,4)
+    A = rand(2,3)
+    @test @inferred(permutedims(SMatrix{2,3}(A))) === SMatrix{3,2}(A')
+    @test @inferred(permutedims(MMatrix{2,3}(A))) isa MMatrix{3,2}
+    @test @inferred(permutedims(MMatrix{2,3}(A))) == A'
+    @test @inferred(permutedims(SizedMatrix{2,3}(A))) isa SizedMatrix{3,2}
+    @test @inferred(permutedims(SizedMatrix{2,3}(A))) == A'
+end
+
 @testset "vcat() and hcat()" begin
     @test @inferred(vcat(SVector(1,2,3))) === SVector(1,2,3)
     @test @inferred(hcat(SVector(1,2,3))) === SMatrix{3,1}(1,2,3)